Ac impedance techniques to study oxidation process of tunnel barriers in CoFe- AlO x -CoFe magnetic tunnel junctions

J. C.A. Huang, C. Y. Hsu

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

The complex impedance spectra of CoFe- AlOx -CoFe tunnel junctions with under-, proper-, and overoxidized tunnel barriers have been investigated by ac impedance techniques. Two sets of parallel resistance (R) and capacitance (C) elements and a R element in series, modeling the impedance contributions of the metal-oxide interfaces and bulk insulating layers, are employed to describe the impedance spectra of under- and proper-oxidized junctions. This model, however, reveals a discrepancy for overoxidized junctions. This discrepancy can be reconciled by including a third set of parallel RC element, which suggests the appearance of overoxidized CoFeOx layer upon the bottom electrode. From further analysis of interfacial capacitance as a function of oxidation time, the bottom interfacial capacitance widely diverges from the top interfacial capacitance and can be related to the oxidation process of tunnel barrier. The analyzing results of impedance technique are also consistent with the results by complex capacitance technique.

Original languageEnglish
Article number064901
JournalJournal of Applied Physics
Volume98
Issue number6
DOIs
Publication statusPublished - 2005 Sep 15

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Fingerprint

Dive into the research topics of 'Ac impedance techniques to study oxidation process of tunnel barriers in CoFe- AlO <sub>x</sub> -CoFe magnetic tunnel junctions'. Together they form a unique fingerprint.

Cite this